There are many devices available for fluid flow measurement. Mechanical wind vanes and half-cup or propeller anemometers are examples of well-known fluid flow sensors. More sophisticated systems are available for measuring turbulence within a fluid flux.
For example, sonic anemometers are known to have advantages over conventional mechanical anemometers. Sonic anemometers may have no moving parts, require no calibration, and may be very durable, making them particularly well suited for relatively remote or inaccessible locations. Furthermore, sonic anemometers have a faster response time and are more accurate and precise than conventional mechanical anemometers. Generally, the sonic anemometers employ a plurality of ultrasonic transducers to generate and receive ultrasonic signals. Signal propagation times along linear paths between transducers are determined and used to calculate wind speed and direction. The determination may be in three dimensions and the sonic anemometer may be operable to measure wind in any direction relative to the anemometer.
Another example of a sophisticated fluid flux sensor is a heated element fluid flow sensor. Heated element fluid flow sensors may be used to measure fluid velocity based on the amount of heat transported away by a fluid passing a heated element. The amount of heat lost is a function of the fluid velocity passing the element. In a typical heated element fluid flow sensor, a hot wire or film is, for example, heated to a constant temperature, maintained at a constant voltage, or maintained at a constant current.